Very often, foods are prepared in single-use containers, or so-called single-use utensils. Especially for foods intended for fast consumption, the expense of cleaning the utensils is thus saved.
Utensil parts made of paperboard have long been known. To be sure, the mere use of paperboard would lead to a very rapid softening of the single-use utensil, or single-use container, and early unserviceability thereof. For this reason, such utensil parts are generally provided with a coating impermeable to water.
The disadvantage of softening is avoided entirely with utensil parts of plastic.
However, these types of single-use utensil have the disadvantage that they entail a considerable environmental stress, because they are degraded only with difficulty or not at all.
To avoid this disadvantage, German Letters of Disclosure DE 4,235,033 A1 discloses an edible single-use plate and a method of producing said single-use plate.
It is there specified that this single-use plate is made from a bread dough by baking. The bread dough contains a rye flour component, not specified in detail. To produce the container mold, cores are provided on a baking tin, over which the bread dough is drawn in baking. Then the bread dough, with no further molding of the outer contour, is baked, leaving an irregular outer shape. If several containers are produced side by side in this manner, provision is made for perforations or incisions between the containers, permitting separation by the user.
After baking, the containers may be inverted, so that the concavity formed by the mold cores becomes the receiving cavity of the container.
Such containers made of bread dough may be used for short-term serving of foods. Here, they are especially suitable for human consumption, but may alternatively be disposed of as animal feed if not consumed. A problem is the prolonged keeping of foods in such containers, since softening is to be expected after only a short time. Besides, such containers manifest a rather bulky outer shape, so that they would seem unsuitable for mass consumption.
German Patent 4,239,143 C2 likewise specifies an edible container whose primary function, however, consists in shaping containers intended for consumption of edible ices in their final form directly on the seller's premises, thus avoiding transport of prefabricated ice containers, which regularly leads to considerable losses due to fragility. For this purpose, in a first heating and baking step, containers are produced in the form of a baked waffle. These are then remoistened and packaged. Owing to the remoistening, the sheets become soft and are transportable with no problems. On the consumer's premises, these sheets can then be removed, dried in another heating step, and finally shaped into their final form. Such containers, owing to the requisite dough composition, have an endurance of several minutes after loading with edible ice, regularly sufficient in the consumption of edible ices. However, use of such edible containers for serving other foods, especially over longer periods of time, is not feasible.
German Letters of Disclosure 4,106,376 A1 likewise disclose a hollow baked product usable as an edible utensil. Here, a dough is pre-formed by a heating operation in a mold chamber. Then, the dough is baked open. Here, the premise is that a rising dough is employed, filling the mold chamber completely in the baking process after a rising operation.
For mass production of such containers, the two necessary steps of heating and then baking uncovered appear to involve a considerable outlay. Besides, the rising dough exhibits a comparatively low long-term stability upon incorporation in food, since moisture contained in the foods may enter the residual gas inclusions with comparative ease, thus softening the container from the inside.
Lastly, German Letters of Disclosure 4,221,018 A1 disclose a single-use container, preferably in the shape of a dish, produced using dough prepared from cereal flour and water, molded and then baked or dried.
This known method provides that the dough be prepared using lye as liquid component. This utilizes the property of the lye that coagulates the albumen contained in the dry substance, for example in the flour, with the lye. The consequent coagulation of the protein forms a lattice filled by the fillers still remaining in the dough, such as starch, cellulose and the like. This method yields products of a leather-like consistency, possessing a good density and resistance to softening.
A disadvantage of this method is that for reliable preparation, a sufficient proportion of coagulable albumen must always be present. Thus, in German Letters of Disclosure 4,221,018 A1, albumen proportions from 10 to 20% of the dry substance are specified.
To achieve such a high protein content, a first possibility consists in employing wheat flour of high purity. Wheat flour has a protein content of 11.2 mass-%, but rye flour by contrast only 7.5 mass-% for example. Protein separated from cereal flour may also be added to the dough. The first case shows that dough in which only wheat flour is used is difficult to detach from the substrate upon kneading. Such dough therefore involves considerable processing difficulty, a disadvantage especially for purposes of mass production.
The second possibility, that is, addition of protein, has the disadvantage that such protein supplementation involves an additional expenditure.